Perceptual and conceptual information processing in schizophrenia and depression.

Schizophrenic patients (n = 20), depressive patients (n = 20), and normal adults (n = 20) were compared on global vs local analyses of perceptual information using tachistoscopic tasks and on top-down vs bottom-up conceptual processing using card-sort tasks. The schizophrenic group performed more poorly on tasks requiring either global analyses (counting lines when distracting circles were present) or top-down conceptual processing (rule learning) than they did on tasks requiring local analyses (counting heterogeneous lines) or bottom-up processing (attribute identification). The schizophrenic group appeared not to use conceptually guided processing. Normal adults showed the reverse pattern. The depressive group performed similarly to the schizophrenic group on perceptual tasks but closer to the normal group on conceptual tasks, thereby appearing to be less dependent on a particular information-processing strategy. These deficits in organizational strategy may be related to the use of available processing resources as well as the allocation of attention.